Question

I was wondering if MySQL has some kind of default alias for the current table you are building (like ‘self’ in SmallTalk or ‘this’ in Java). For instance:

SELECT 
SUM(revenue) AS revenue,
SUM(units) AS units,
SUM(revenue)/SUM(units) AS revPerUnit,
-- I want to replace the above line with the below line:
self.revenue/self.units AS revPerUnit2
FROM inputTable;

I know that I could just use unabiguous aliases, but I want to know if there is a way to specify that you want the current table’s alias when there exists an ambiguous definition.

Answer 1

Usually, this is what I do on these cases:

SELECT revenue, 
       units, 
       revenue / units AS revperunit2 
FROM   (SELECT SUM(revenue) AS revenue, 
               SUM(units)   AS units 
        FROM   inputtable) subsel 

Sometimes you have complicated queries and re-declaring the fields is not good for readability neither is for performance. Sub queries is the way to go.